1. Field of the Invention
The present invention relates to a gripping apparatus mounted on an arm of a robot, a robot system including a robot having a gripping apparatus, and a gripping method in which a gripping apparatus grips a gripping object.
2. Description of the Related Art
Heretofore, a robot system including a robot having a gripping apparatus has been known. In recent years, there has been demanded a robot system which realizes a manual assembling operation by a robot. Moreover, in the manual assembling operation, conveyors are removed, and a person cell production system is introduced in which persons directly convey workpieces, but for the purpose of replacing person cells with robot cells, a robot system is demanded which grips various parts to perform the assembling operation. Moreover, a robot system is demanded in which a robot performs an assembling operation by use of an assembling tool and an assembling jig such as a screwdriver and a dispenser, whereby the robot can perform the operation in the same manner as in person. In this case, it is necessary to grip various assembling tools.
At this time, in order to precisely perform the assembling operation, it is required to set a positioning reproduction precision to a high precision in a case where the gripping apparatus grips a gripping object such as the assembling tool. That is, every time the workpiece is changed, the robot repeats the same operation. Therefore, the gripping apparatus needs to repeat a similar gripping operation. In this case, it is required that the positioning reproducibility of the gripping object is improved to precisely position the gripping object. In particular, it is necessary to precisely position a gripping object such as the assembling tool at an operating position (a bit tip in the case of the screwdriver and a needle tip in the case of the dispenser). On the other hand, heretofore there has been suggested a gripping apparatus including a palm having a V-shaped guide groove which guides the gripping object to regulate a posture thereof when gripping the gripping object (see Japanese Patent Application Laid-Open No. H09-029675).
However, in the above conventional gripping apparatus, the posture of the gripping object can be regulated, but a direction of the gripping object along the guide groove is not regulated, whereby it is not possible to precisely position the gripping object. When the gripping object is a tool such as the screwdriver, the tool is not positioned in a longitudinal direction. Therefore, the tip of the tool cannot precisely be positioned with respect to the workpiece.
To solve the problem, an object of the present invention is to provide a gripping apparatus which improves a positioning reproducibility of a gripping object when gripping the gripping object, whereby the gripping object can precisely be positioned, and to provide a robot system and a gripping method.